Jun 15, GianCarlo Ghirardi, former professor of theoretical physics and then emeritus at the physics department of our university, passed away on 1st. GianCarlo Ghirardi. Angelo Bassi and Tullio Weber. University of Trieste, Trieste, Italy. Detlef Dürr. Ludwig-Maximilians University, Munich, Germany. PDF Full. Jun 4, The ICTP community is mourning the sudden passing of long-time colleague GianCarlo Ghirardi. Professor Ghirardi was associated with ICTP.
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As regards the first point, it should be enough to recall the debate between Bohr and Einstein that we analyzed in detail in chapter 7. Schematic representation of a measuring apparatus with the pointer in position 0, which indicates that it is ready giancrlo register the arrival of a photon either in the upper shaded region U or in the lower shaded region L.
Dieter Zeh Ernst Zermelo. The idea that a giqncarlo pointer can point simultaneously in different directions, or that a cat can have several of its nine lives at the same time, is harder to swallow.
Giancarlo Ghirardi – Wikipedia
Furthermore, while the quantum dynamics is perfectly reversible, as in the classical case, the giacnarlo of the reduction of the wave packet is fundamentally irreversible. At least two roads are open from there towards a precise theory, it seems to me. Bell analyzed the process of diffraction, through a slit, of a beam containing a certain number N of electrons, and the formation of the image on a photographic film placed giancarpo the slit.
As discussed in Section The problem that remains, and which is of no small account, is that of succeeding in identifying in a nonambiguous way the boundary line between these two levels of the real, which require two essentially different and irreconcilable physical descriptions.
Jonathan Lowe John R. Here is an image John Bell proposed to illustrate this deep question. But even the brain is a physical system constituted of protons, neutrons, and electrons, and traversed by electrochemical reactions and the rest—processes that we have no reason to giqncarlo are not governed by our formalism.
The relevant physical implications of the enormous complexity of the apparatus will emerge when we pose the problem of how to “verify in the laboratory” that in fact, at the end, there is a superposition of macroscopically distinguishable states.
Why this aversion to ‘being’ and insistence on ‘finding’?
If we want to describe which signals actually reach the brain, we would once more have to relocate the boundary between the vague quantum world and the world of definite events, and we are then led to place it between the optic nerve and the brain. The President of the Province of TriesteMaria Teresa Bassa Poropatconferred the Hhirardi della Provincia di Trieste to Giancarlo Ghirardi for research and teaching, for his commitment to the promotion and development of physics in Trieste and for his intense and fruitful activity as the author of popular books and scientific publications.
He observed that it makes no sense to treat the electrons as if they were punctifom bodies that follow precise trajectories; they must be described by means of a diffracting wave function Figure In addition to the GRW theory, added Quevedo, Ghirardi made other important scientific contributions which are less known. To my knowledge, the most mathematically rigorous demonstration of the fact that the very possibility of using measuring apparatuses with a high degree of reliability implies the indefiniteness of some of their macroscopic properties, appears in a paper which I recently wrote in collaboration giacarlo my doctoral student A.
Although GRW thirardi the wave function collapse, and their mathematics is “precise,” they still can not predict exactly when the collapse occurs. The big question, in my opinion, is which, if either, of these two precise pictures can be redeveloped in a Lorentz invariant way. The X s are somehow macroscopic.
Bell had criticized the work of John von Neumannwho could not locate the boundary between the quantum system and the classical measuring apparatus. Von Neumann said the cut could be located anywhere from the atomic system up to the mind giancaelo the conscious observer, injecting an element of subjectivity into the understanding.
Scientists Michael Arbib John S. For simplicity we will suppose, with von Neumann, that the photon passes through the apparatus without changing its state. But this does not change in the least the objective “given” that such a superposition must be considered present whenever it is assumed that we have at our disposal an apparatus that reliably allows the identification of vertical or horizontal polarization of a photon, and that the interaction between the measured system and the measuring apparatus is a process that obeys the general laws of the theory.
This is not spelled out very explicitly. In this case it is easy to identify a precise parameter: The kinematics of the world, in this orthodox picture, is given a wavefunction maybe more than one?
To take up the problem it will be convenient to analyze first of all the case in which a vertically polarized photon is sent into a birefringent crystal placed in front of the apparatus.
He was president of the Italian Society for the Foundations of Physics, of which he was one of the founding members.